While sandbags come in different sizes, the optimal size is 14–18 in (36–46 cm) wide and 30–36 in (76–91 cm) deep. You can get sandbags with drawstrings built into them to make tying easier. If you’re buying bags to build a flood wall, you don’t actually have to tie them, though.
Soil will break apart in your bag and leak through the woven bag if it gets wet, but can work if you’re only trying to brace a surface. You can use a mixture of sand and soil if you don’t have enough sand to fill the bags you need. Gravel will work if you’re trying to weigh a surface down, but it is too permeable to keep water out. Clay materials are hard to shape and will make stacking difficult.
You’ll have to be extremely careful when you’re pouring your sand into the bag if you’re doing it yourself. You may become exhausted as well if you’re building a sandbag wall, since lifting and laying the bags requires heavy lifting. Rotate positions every 20 minutes to reduce muscle fatigue.
Avoid touching your skin, eyes, or mouth while filling sandbags. Wash your hands and face when you’re done.
Sandbags should only be filled 2/3 full. Folding the top of the bag over also makes it easier to see how much sand you’re adding.
Don’t work too quickly. If you wear yourself out, it’ll become difficult to shovel accurately. If it’s a little windy or you’re having trouble filling the bag, put a large funnel in the mouth of the bag. Pour the sand into the funnel to make the filling process easier.
If you have bags with built-in ties at the top, they can be filled until they’re 4/5 full. Bags with built-in ties don’t require as much room to secure them. Repeat this process until you have the desired number of bags.
You may have an easier time securing thinner bags if you only fill them so that they’re halfway filled.
Bags that are folded on top of themselves will stay in place when they’re stacked in a wall.
